Idiopathic Ventricular Arrhythmias Originating From the Aortic Root

Prevalence and electrocardiographic and electrophysiological characteristics of idiopathic ventricular arrhythmias originating from the septal left ventricular summit

INTRODUCTION

The left ventricular summit (LVS) is the highest point on the epicardial surface of the left ventricle. A part of the LVS that is located between the left coronary arteries (lateral-LVS) is one of the major sites of idiopathic ventricular arrhythmia (VA) origins. Some idiopathic epicardial VAs can be ablated at endocardial sites adjacent to the epicardial area septal to the lateral-LVS (septal-LVS). This study examined the prevalence and electrocardiographic and electrophysiological characteristics of septal-LVS VAs.

METHODS

We studied consecutive patients with idiopathic VAs originating from the LVS (67 patients) and aortic root (93 patients).

RESULTS

Based on the ablation results, among 67 LVS VAs, 54 were classified as lateral and 13 as septal-LVS VAs. As compared with the lateral-LVS VAs, the septal-LVS VAs were characterized by a greater prevalence of left bundle branch block with left inferior-axis QRS pattern, later precordial transition, lower R-wave amplitude ratio in leads III to II, lower Q-wave amplitude ratio in leads aVL to aVR, and later local ventricular activation time relative to the QRS onset during VAs (V-QRS) in the great cardiac vein. The electrocardiographic and electrophysiological characteristics of the septal-LVS VAs were similar to those of the aortic root VAs. However, the V-QRS at the successful ablation site was significantly later during the septal-LVS VAs than aortic root VAs (p < .0001). The precordial transition was significantly later during the septal-LVS VAs than aortic root VAs (p < .05).

CONCLUSIONS

Septal-LVS VAs are considered a distinct subgroup of idiopathic VAs originating from the left ventricular outflow tract.

Natural increase in the efficiency of ablation of ventricular tachyarrhythmias using high-density mapping in patients with non-ischemic etiology

OBJECTIVE

This research is aimed at evaluating the efficacy and safety of ablation of ventricular tachyarrhythmias using high-density mapping in patients with non-ischemic etiology.

MATERIAL AND METHODS

This study analyzed 60 patients with ventricular tachyarrhythmias, using diagnostic tools like electrocardiography and MRI. Treatment involved epicardial ablation following the E. Sosa method, with efficacy evaluated through the SF-36 survey and MRI. Success rates were categorized, and post-treatment care included troponin monitoring and aspirin. Data was analyzed using Excel and Statistika 11.0.

RESULTS

Of the 60 patients, 30 underwent surgery at the City Cardiological Center in Almaty and 30 patients were operated on at the National Research Cardiac Surgery Center in Astana. Prior to surgery, all patients underwent a standard clinical diagnostic examination followed by ablation of ventricular tachyarrhythmias using high-density mapping. After six and 12 months from the beginning of the study, all patients underwent a follow-up examination, with an assessment of the effectiveness of the above treatment. After 12 months, follow-up examination of patients showed good results. Left ventricular ejection fraction in patients after 12 months increased from 47 ± 2.4 to 58 ± 4.5%. The end-diastolic diameter of the left ventricle decreased from 61.2 ± 2.31 to 50.1 ± 1.9 mm.

CONCLUSION

In summary, the study highlights the efficacy and safety of high-density mapping ablation in treating ventricular tachyarrhythmias, especially from the right ventricular outflow tract in patients with reduced left ventricular ejection fraction. The success rate of the procedure was 95%. This approach proves beneficial for patients unresponsive to antiarrhythmic therapy, enhancing both the quality of life and potentially reducing mortality in patients with ventricular arrhythmias.

Trends Favoring an Anatomical Approach to Radiofrequency Catheter Ablation of Idiopathic Ventricular Arrhythmias Originating From the Left Ventricular Summit

BACKGROUND

Epicardial radiofrequency catheter ablation (RFCA) of idiopathic ventricular arrhythmias (VAs) originating from the left ventricular summit (LVS) is challenging because of the anatomic barriers. On the other hand, RFCA at the endocardial sites near the earliest epicardial activation site of LVS-VAs (anatomic approach) has proven successful. The evolving trends in the approaches and outcomes of RFCA of LVS-VAs at a single center were evaluated.

METHODS

We studied 88 consecutive patients with idiopathic LVS-VAs at our institute from 2009 to 2019. These patients were divided into 3 periods: 2009 to 2012 (early), 2013 to 2015 (middle), and 2016 to 2019 (recent). The data were compared among the 3 periods.

RESULTS

The RFCA success rate did not significantly change from the early to middle period but significantly increased from the middle to recent period (P=0.0315). The transpericardial approach usage significantly decreased over the 3 periods. The anatomic approach usage significantly increased over the 3 periods. The use of the transpericardial approach did not affect the RFCA outcomes over the 3 periods. The success rate of the anatomic RFCA tended to increase from the early to middle period and significantly increased from the middle to recent period (P=0.0412). The number of endocardial locations where RFCA was successful increased over the 3 periods.

CONCLUSIONS

Over the 10-year period, the transpericardial approach became decreasingly performed, whereas the anatomic approach became increasingly performed with a satisfactory improvement in the RFCA outcomes of LVS-VAs. The anatomic RFCA became more successful by identifying more and various endocardial locations as target sites.

RV1+RV3 Index to Differentiate Idiopathic Ventricular Arrhythmias Arising From Right Ventricular Outflow Tract and Aortic Sinus of Valsalva: A Multicenter Study

BACKGROUND

This study aimed to investigate the predictive value of parameters of every precordial lead and their combinations in differentiating between idiopathic ventricular arrhythmias (IVAs) from the right ventricular outflow tract and aortic sinus of Valsalva (ASV).

METHODS AND RESULTS

Between March 1, 2018, and December 1, 2021, consecutive patients receiving successful ablation of right ventricular outflow tract or ASV IVAs were enrolled. The amplitude and duration of the R wave and S wave were measured in every precordial lead during IVAs. These parameters were either summed, subtracted, multiplied, or divided to create different indexes. The index with the highest area under the curve to predict ASV IVAs was developed, compared with established indexes, and validated in an independent prospective multicenter cohort. A total of 150 patients (60 men; mean age, 45.3±16.4 years) were included in the derivation cohort. The RV1+RV3 index (summed R-wave amplitude in leads V1 and V3) had the highest area under the curve (0.942) among the established indexes. An RV1+RV3 index >1.3 mV could predict ASV IVAs with a sensitivity of 95% and a specificity of 83%. Its predictive performance was maintained in the validation cohort (N=109). In patients with V3 R/S transition, an RV1+RV3 index >1.3 mV could predict ASV IVAs, with an area under the curve of 0.892, 93% sensitivity, and 75% specificity.

CONCLUSIONS

The RV1+RV3 index is a simple and novel criterion that accurately differentiates between right ventricular outflow tract and ASV IVAs. Its performance outperformed established indexes, making it a valuable tool in clinical practice.

Experience of left ventricular outflow tract arrhythmia ablation in paediatric patients using limited fluoroscopy and three-dimensional mapping technique

OBJECTIVE

The left ventricular outflow tract is an important source of ventricular arrhythmias. Up to one-third of all idiopathic ventricular arrhythmias in patients with structurally normal hearts may arise from this region. We would like to share the results of our left ventricular outflow tract ablation using three-dimensional mapping and limited fluoroscopy.

MATERIALS AND METHODS

This is a single-centre retrospective cohort study. Forty-six consecutive patients who underwent left ventricular outflow tract ablation procedures between January 2015 and June 2023 were included in the study. The EnSite Precision System (Abbott, St. Paul, MN, USA) was used to facilitate mapping and to reduce or eliminate the need for fluoroscopy.

RESULTS

The study group comprised 29 males and 17 females, with a mean age of 13.4 ± 4.5 years. The most common location for arrhythmias was the left coronary cusp (n : 21). Other locations, in sequence, included the junction of the right and left coronary commissure (n : 10), right coronary cusp (n : 10), left ventricular outflow tract endocardium (n:4), aorto-mitral junction (n : 1), and great cardiac vein (n : 1). Nine of these patients had previously undergone unsuccessful right ventricular outflow tract ablation at another centre. Cryoablation was performed in three patients, irrigated radiofrequency ablation in three patients, and conventional radiofrequency ablation in the remaining patients. The acute success rate was 100%, and no recurrences were observed. The mean follow-up period was 49.6 ± 24.4 months. All patients were asymptomatic and were being followed without antiarrhythmic medication.

CONCLUSION

Although left ventricular outflow tract ablations pose a risk for coronary artery and heart valve complications, they can be performed successfully and safely with the guidance of three-dimensional mapping.

Lead I R-wave indexes: A novel electrocardiographic criterion for distinguishing the origin of idiopathic premature ventricular contractions from the three subregions of the aortic sinus cusps

PURPOSE

The current study was conducted to investigate the electrocardiographic (ECG) characteristics of idiopathic premature ventricular contractions (PVCs) originating from the aortic sinus cusp (ASC) and establish a novel ECG criterion to discriminate PVCs originating from the right coronary cusp (RCC), left coronary cusp (LCC), and the left and right coronary cusp junction (LRJ).

METHODS

A retrospective analysis was performed on a total of 133 patients with idiopathic PVCs who underwent successful mapping and ablation. The sites of origin (SOO) were confirmed using fluoroscopy and a three-dimensional mapping system during radiofrequency catheter ablation (RFCA). Among the patients, 69 had PVCs originating from the LCC, 39 from the RCC, and 25 from the LRJ. Characteristics of surface 12‑lead electrocardiograms (ECGs) recorded during PVCs were analyzed. Q-, R-, S, and R'-wave amplitudes were measured in lead I, and the lead I R-wave indexes (IRa, IRb, IRc, IRd, and IRe) were derived by employing multiplication, subtraction, sum, and division operations on these ECG measurements. Notably, IRb and IRe demonstrated usefulness as ECG indexes for discriminating PVCs originating from RCC, LCC, and LRJ in the ASC.

RESULTS

The R- and S-wave amplitudes in lead I exhibited statistically significant differences among the three groups (P < 0.001 and P < 0.001, respectively). In discriminating PVCs originating from the RCC from the other two groups, IRb showed the largest area under the curve (AUC) of 0.813, as assessed by receiver operating characteristic (ROC) analysis, with a cutoff value of ≤0.5 indicating PVCs of RCC origin. The sensitivity and specificity were 80.3% and 78.7%, respectively. For discriminating PVCs arising from the LCC from those in the LRJ group, IRe exhibited the largest AUC of 0.801, with an optimal cutoff value of 0. An IRe value >0 indicated PVCs originating from the LRJ, while an IRe value ≤0 indicated PVCs originating from the LCC. The sensitivity and specificity of the IRe index were 84.0% and 70.7%, respectively.

CONCLUSION

Lead I R-wave indexes provided simple and useful ECG criteria for discriminating PVCs originating from the LCC, RCC, and LRJ in the left ventricular outflow tract (LVOT).

Catheter ablation of intramural outflow tract premature ventricular complexes: a multicentre study

AIMS

Ablation of outflow tract ventricular arrhythmias may be limited by a deep intramural location of the arrhythmogenic source. This study evaluates the acute and long-term outcomes of patients undergoing ablation of intramural outflow tract premature ventricular complexes (PVCs).

METHODS AND RESULTS

This multicenter series included patients with structurally normal heart or nonischemic cardiomyopathy and intramural outflow tract PVCs defined by: (a) ≥ 2 of the following criteria: (1) earliest endocardial or epicardial activation < 20ms pre-QRS; (2) Similar activation in different chambers; (3) no/transient PVC suppression with ablation at earliest endocardial/epicardial site; or (b) earliest ventricular activation recorded in a septal coronary vein. Ninety-two patients were included, with a mean PVC burden of 21.5±10.9%. Twenty-six patients had had previous ablations. All PVCs had inferior axis, with LBBB pattern in 68%. In 29 patients (32%) direct mapping of the intramural septum was performed using an insulated wire or multielectrode catheter, and in 13 of these cases the earliest activation was recorded within a septal vein. Most patients required special ablation techniques (one or more), including sequential unipolar ablation in 73%, low-ionic irrigation in 26%, bipolar ablation in 15% and ethanol ablation in 1%. Acute PVC suppression was achieved in 75% of patients. Following the procedure, the PVC burden was reduced to 5.8±8.4%. The mean follow-up was 15±14 months and 16 patients underwent a repeat ablation.

CONCLUSION

Ablation of intramural PVCs is challenging; acute arrhythmia elimination is achieved in 3/4 patients, and non-conventional approaches are often necessary for success.

Gross anatomic relationship between the human left atrial appendage and the left ventricular summit region: implications for catheter ablation of ventricular arrhythmias originating from the left ventricular summit

PURPOSE

The left ventricular summit (LVS) is a source of difficult-to-treat arrhythmias because of anatomical limitations. The aim of this study was to perform detailed research of the left atrial appendage (LAA) anatomy of cadaveric hearts to analyze their complex anatomy and coverage of the LVS.

METHODS AND RESULTS

Eighty human formalin fixed hearts (mean age 44.4 ± 15.5, 27.5% females) were investigated. Each LAA size, type, and its relationship to the LVS were analyzed, as well as possible access sites for mapping/ablating electrode. Four types of LAA were observed over two LVS sites that are either accessible or not. The highest coverage over an inaccessible LVS area was observed in the Broccoli type, followed by the Windsock then the Chicken Wing and finally the Cactus types; over the accessible area of the LVS was observed in the Windsock, then in the Chicken Wing, then in the Cactus, and finally in the Broccoli types. The attainable coverage for electrode access is diminished from 25 to 65% because of the complex pectinate muscles and sharp angles. The highest density of the LAA floor made by pectinate muscles can be found in the Broccoli type (p < 0.005), while the Chicken Wing had the highest number of paper-thin-like pouches.

CONCLUSIONS

The LAA appears to be a promising entry for ablation-qualified patients with the LV summit originate arrhythmias. The complex internal structure of the LAA may complicate ablation procedures. More prominent appendages are promising in more extensive mapping areas over the LVS.

Predictors of Successful Endocardial Ablation of Epicardial Left Ventricular Summit Arrhythmias

Endocardial catheter ablation of ventricular arrhythmias (VAs) originating from the left ventricular summit (LVS) at remote structures adjacent to the LVS may be an alternative (anatomic approach) but may not be so successful. This type of catheter ablation is successful most commonly in the left ventricular outflow tract followed by the aortic cusps and rarely in the right ventricular outflow tract. A right bundle branch block QRS morphology and anatomic distance between the earliest ventricular activation site in the coronary venous system and endocardial ablation site (<13 mm) could be predictors of a successful endocardial catheter ablation of LVS VAs.

A novel practical algorithm using machine learning to differentiate outflow tract ventricular arrhythmia origins

INTRODUCTION

Diagnosis of outflow tract ventricular arrhythmia (OTVA) localization by an electrocardiographic complex is key to successful catheter ablation for OTVA. However, diagnosing the origin of OTVA with a precordial transition in lead V3 (V3TZ) is challenging. This study aimed to create the best practical electrocardiogram algorithm to differentiate the left ventricular outflow tract (LVOT) from the right ventricular outflow tract (RVOT) of OTVA origin with V3TZ using machine learning.

METHODS

Of 498 consecutive patients undergoing catheter ablation for OTVA, we included 104 patients who underwent ablation for OTVA with V3TZ and identified the origin of LVOT (n = 62) and RVOT (n = 42) from the results. We analyzed the standard 12-lead electrocardiogram preoperatively and measured 128 elements in each case. The study population was randomly divided into training group (70%) and testing group (30%), and decision tree analysis was performed using the measured elements as features. The performance of the algorithm created in the training group was verified in the testing group.

RESULTS

Four measurements were identified as important features: the aVF/II R-wave ratio, the V2S/V3R index, the QRS amplitude in lead V3, and the R-wave deflection slope in lead V3. Among them, the aVF/II R-wave ratio and the V2S/V3R index had a particularly strong influence on the algorithm. The performance of this algorithm was extremely high, with an accuracy of 94.4%, precision of 91.5%, recall of 100%, and an F1-score of 0.96.

CONCLUSIONS

The novel algorithm created using machine learning is useful in diagnosing the origin of OTVA with V3TZ.

Utility of high resolution mapping to guide ablation of ventricular arrhythmias from the aortic sinuses of Valsalva

PURPOSE

Left ventricular outflow tract (LVOT) arrhythmias are commonly targeted from the aortic sinuses of Valsalva (SOV). Both presystolic potentials during ventricular arrhythmia (VA) and late diastolic potentials during sinus rhythm have been recognized as markers of successful ablation sites. The study aimed to evaluate the utility of high resolution mapping (HRM) with small and closely spaced electrodes for guiding ablation of VA from the SOV.

METHODS

Seventeen patients with LVOT VA underwent HRM in the SOV with either PentaRay (13) or Orion (4) catheters. Ablation was guided by low amplitude high frequency potentials that were identified with HRM and tagged on the electroanatomic map.

RESULTS

High frequency low amplitude potentials during sinus rhythm (late) or VA (early) were demonstrated with HRM in all 17 consecutive patients; while these potentials were either absent or usually had a far-field appearance in the recordings obtained at the same sites with a 3.5-mm standard ablation catheter. On intracardiac echocardiogram, sites with these potentials corresponded to the bases of the sinuses adjacent to the LV ostium. Ablation was acutely successful in 16 out of 17 patients. Significant reduction in VA burden (≥ 90%) was noted in 15 patients.

CONCLUSIONS

High frequency low amplitude potentials during sinus rhythm (late) and VA (early) are consistently recorded using HRM in the SOV in patients with VA arising from the aortic sinuses of Valsalva. Standard ablation catheters have limited resolution for detecting these potentials. HRM may potentially improve outcomes of ablation of VA originating from the aortic SOV.

Techniques for Catheter Ablation of Idiopathic Ventricular Arrhythmias Originating from the Outflow Tract and Left Ventricular Summit

Idiopathic ventricular arrhythmias (VAs) most commonly originate from the ventricular outflow tracts. Because the anatomy of this region is complex and some of those VA origins are intramural and epicardial, it may sometimes be difficult to locate the site of the VA origin. Meticulous mapping in multiple different locations such as the right and left ventricular outflow tracts, endocardial and epicardial sites, and above and below the aortic and pulmonic valves may be required to achieve successful catheter ablation of those VAs. Special ablation techniques may be considered to improve the outcome of catheter ablation of intramural and epicardial VAs.

A Four-Stepwise Electrocardiographic Algorithm for Differentiation of Ventricular Arrhythmias Originated from Left Ventricular Outflow Tract

Several electrocardiographic algorithms have been proposed to identify the site of origin for the ventricular arrhythmias (VAs) from the left ventricular outflow tract (LVOT) versus right ventricular outflow tract. However, the electrocardiographic criteria for distinguishing VAs originated from the different sites of LVOT is lacking. We aimed to develop a simple and efficient ECG algorithm to differentiate LVOT VAs originated from the aortic root, AMC and LV summit. We analyzed 12-lead ECG characteristics of 68 consecutive patients who underwent successful radiofrequency catheter ablation of symptomatic VAs from LVOT. Patients were divided into RCC (right coronary cusp) group (n = 8), the L-RCC (the junction between the LCC and RCC) group (n = 21), the LCC (left coronary cusp) group (n = 24), the aortomitral continuity (AMC) group (n = 9) and the LV summit group (n = 6) according to the final ablation sites. Measurements with the highest diagnostic performance were modeled into a 4-stepwise algorithm to discriminate LVOT VAs. The performance of this novel algorithm was prospectively tested in a validation cohort of 43 consecutive patients undergoing LVOT VAs ablation. Based on the accuracy of AUC, a 4-stepwise ECG algorithm was developed. First, the QS duration in aVL > 134 ms was used to distinguish VAs from AMC, LV summit and VAs from aortic root (80% sensitivity and 76% specificity). Second, the R duration in II > 155 ms was used to differentiate VAs from LV summit and VAs from AMC (67% sensitivity and 56% specificity). Third, the ratio of III/II < 0.9 was used to discriminate VAs from RCC and VAs from LCC, L-RCC (82% sensitivity and 63% specificity). Fourth, the QS duration of aVR > 130 ms was used to discern VAs from LCC and VAs from L-RCC (75% sensitivity and 62% specificity). In the prospective evaluation, our 4-stepwise ECG algorithm exhibited a good predictive value. We have developed a novel and simple 4-stepwise ECG algorithm with good predictive value to discriminate the AVs from different sites of LVOT.

Very-high-power short-duration ablation for treatment of premature ventricular contractions – The FAST-AND-FURIOUS PVC study

Objectives

We sought to assess the efficacy, safety and short-term clinical outcome of very high-power short-duration (vHP-SD) radiofrequency (RF) catheter ablation for the treatment of idiopathic PVCs originating from the cardiac outflow tract (OT).

Background

Power-controlled RF ablation is a widely used technique for the treatment of premature ventricular contractions (PVCs). A novel ablation catheter offers three microelectrodes and six thermocouples at its tip and provides temperature-controlled vHP-SD (90 Watts/4 s,) with the opportunity to switch to moderate-power mode.

Methods

In this pilot study, twenty-four consecutive, prospectively enrolled patients underwent PVC ablation utilizing the vHP-SD ablation (study group) and were compared with 24 consecutive patients previously treated with power-controlled ablation (control group). Each group included 12 patients with PVCs originating from the right ventricular OT (RVOT) and 12 patients with PVCs originating from the left ventricular OT (LVOT). The acute endpoint was PVC elimination and was achieved in all patients.

Results

In 16/24 (67%) patients (study group) it was achieved by using vHP-SD only. The median RF delivery time was 52 (interquartile range [IQR] 16, 156) seconds (study group) and 350 (IQR 240, 442) seconds (control group, p < 0.0001). No difference was observed regarding procedure duration (p = 0.489) as well as 6-months follow-up (p = 0.712). One (4%, study group) and 2 (8%, control group) severe adverse events occured (p = 0.551).

Conclusion

In this study, vHP-SD PVC ablation was similarly effective and safe as compared to conventional power-controlled ablation. The RF time was significantly shorter.

Don't Forget the Sinuses: an important site for some infarct-related VT

The aortic sinuses of Valsalva are an important ablation site in non-ischemic substrates and in patients with idiopathic ventricular arrhythmias. Siontis and colleagues have demonstrated that these sites should also be considered for ablation in patients with infarct-related inferior axis VT. Low voltage in the aortic sinuses of Valsalva or in the sub-aortic region should prompt further evaluation of these regions for ablation. This article is protected by copyright. All rights reserved.

Ventricular Tachycardia Targeted in the Aortic Sinuses of Valsalva in Patients with Prior Myocardial Infarction

INTRODUCTION

Ventricular tachycardia (VT) in structurally normal hearts or non-ischemic cardiomyopathy can originate from the aortic sinuses of Valsalva (SoV). It is unknown whether VT can originate from the SoVs in patients with prior myocardial infarction (MI).

OBJECTIVE

To evaluate the prevalence, arrhythmogenic substrate, and ablation outcomes of post-infarction VT originating from the SoVs.

METHODS

Among 217 consecutive patients with post-infarction VT undergoing ablation, we identified 13 (6%) patients who had ≥1 VT mapped in a SoV. Control groups of 13 patients with idiopathic SoV VT and 13 post-infarction patients without SoV VT were included.

RESULTS

In the study group, 17 VTs were mapped in a SoV (right n=5, left-right commissure n=6, left n=6). SoV VT target sites had low bipolar voltage during sinus rhythm [median 0.42 (IQR 0.16-0.53) mV] which was significantly lower than target sites in patients with idiopathic SoV VTs [median 1.02 (IQR 0.89-1.52) mV; p<0.001]. An area of endocardial low voltage was found below the aortic valve in all patients with post-infarction SoV VTs compared to 9 (69%) of the patients in the post-infarction control group without SoV VT (p=0.02). Morphology characteristics of post-infarction SoV VTs differed from idiopathic SoV VTs. None of the post-infarction SoV VTs were inducible after ablation and none recurred after a median follow-up of 14 months.

CONCLUSION

In patients with prior MI, VT can be targeted in an aortic SoV. The SoVs should be routinely investigated in post-infarction patients with inferior axis VT and an area of low-voltage below the aortic valve. This article is protected by copyright. All rights reserved.

Ventricular premature complexes successfully ablated from the non-coronary cusp: a case report

Background

Ventricular premature complexes (VPCs) occasionally originate from the aortic sinus of Valsalva. Because the anterior part of the left coronary cusp (LCC) and right coronary cusp (RCC) are connected through the ventricular musculature at their bases, VPCs are more common in the LCC and the RCC than in the non-coronary cusp (NCC). We herein report a case in which VPCs were successfully ablated from the NCC, which is considered rare.

Case summary

A 30-year-old woman was admitted to our hospital for the ablation of VPCs, which comprised 43% of the total heart beats. The clinical VPCs had an inferior axis and left bundle branch block morphology with a precordial transition between V4 and V5. Three-dimensional mapping of the target VPCs indicated that the earliest activation site was RCC. After radiofrequency (RF) energy application at the RCC, VPCs were temporally suppressed but recurred after 24 min. Remapping of the recurrent VPCs revealed that the earliest activation site shifted from the RCC to the His region. To avoid the risk of atrioventricular block, RF energy was applied from the NCC, which resulted in successful elimination of the VPCs without any complications.

Discussion

The present case suggests that RF energy application from the NCC may be a safe and effective option for the ablation of VPCs with the earliest activation at the RCC and His region.

Aortic Regurgitation as a Complication of Electrophysiologic Ablation Techniques: A Narrative Review

BACKGROUND

Radiofrequency catheter ablation is a well-established treatment for several cardiac arrhythmias. Arrhythmias originating from the left side of the heart including ventricular and supraventricular tachycardia and ectopy can be successfully ablated through either transseptal or retrograde aortic approach. Although these techniques have a generally low rate of complications, aortic valve injury is a potential complication of ablation at the left cardiac side that warrants more investigation.

OBJECTIVE

The purpose of this review is to evaluate the incidence of iatrogenic aortic valve regurgitation and explore the potential mechanisms and risk factors that might contribute to aortic valve injury during radiofrequency ablation. Additionally, the course and progression of aortic regurgitation in the reported cases will be described.

METHODS

Authors searched PubMed for articles using the keywords "ablation" AND "aortic insufficiency" OR "aortic valve injury" OR "aortic regurgitation". Case reports and series as well as retrospective and prospective studies were included, and relevant review articles and editorial comments were used as a supplementary source of data. A total of 19 references were used and a detailed description of patient characteristics, procedural techniques, and incidence, predictors, and fate of aortic regurgitation were reported by 11 clinical studies.

RESULTS

There is a small risk of significant iatrogenic aortic regurgitation after radiofrequency ablation of left-sided cardiac arrhythmias, especially techniques performed via a retrograde aortic approach.

CONCLUSION

Although the risk is not confined to procedures applying direct energy to the aortic cusp region, a more aggressive ablation applied in the vicinity of the valvular complex seems to be associated with a higher risk. Routine post-procedural surveillance should be adopted to detect de novo aortic valve injury following radiofrequency ablation techniques.

Idiopathic Ventricular Arrhythmias Ablated in Different Subregions of the Aortic Sinuses of Valsalva: Anatomical Distribution, Precordial Electrocardiographic Notch Patterns, and Bipolar Electrographic Characteristics

Background: Little is known about the differences among ventricular arrhythmias (VAs) ablated in different subregions of the aortic sinuses of Valsalva (ASVs). We aim to investigate the distribution, precordial electrocardiographic patterns, and bipolar electrogram characteristics of VAs ablated in different subregions of the ASVs.

Methods: We divided the right ASV and the left ASV into a total of 6 subregions and studied 51 idiopathic VAs ablated first time successfully in the ASVs.

Results: These 51 VAs were inhomogeneously distributed among the 6 subregions, which comprised the right-lateral ASV (1/51), the right-anterior ASV (11/51), the regions along the right (13/51) and left (9/51) sides of the ASV junction, the left-anterior ASV (5/51), and the left-lateral ASV (12/51). Fractionated potentials were dominant (39/51, 76%) among the 3 types of target electrograms. From the right-lateral ASV to the left-lateral ASV, the percentage of fractionated potentials gradually decreased from 100 to 59%. A precordial rebound notch in V3-V4 or V4-V5 had sensitivity of 90.9%, specificity of 85.0%, and negative predictive value (NPV) of 97.1% to predict VAs ablated in the right-anterior ASV. A precordial rebound notch in V2-V3 had sensitivity of 50.0%, specificity of 94.9%, and NPV of 86.0% to predict VAs ablated in the left-lateral ASV.

Conclusion: VA targets were mainly distributed in the anterior and the left-lateral ASVs. Fractionated potentials were common among target electrograms, especially in theright-anterolateral ASV. Precordial electrocardiographic rebound notch has high predictive accuracy in identifying different subregions of the ASVs as target ablation sites.

Ablation with zero-fluoroscopy of premature ventricular complexes from aortic sinus cusps: A single-center experience

BACKGROUND

Catheter ablation of premature ventricular complexes from aortic sinus cusps (ASC-PVC) is a complex procedure that conventionally requires coronary catheterization (CC) to localize coronary artery ostium (CAO). Little published information is available on the mapping and ablation with zero-fluoroscopy (ZF) of ASC-PVC. The aim of the study was to determine the efficacy and safety of ASC-PVC ablation with a ZF approach guided by 3D intracardiac echocardiography integration in the electroanatomical mapping system (ICE 3D-EAM).

METHODS

This observational study included one patient cohort treated conventionally and another treated with ICE 3D-EAM-guided ZF ablation. Clinical, efficacy, and safety outcomes were evaluated acutely and at 3 months follow-up.

RESULTS

The study included 21 patients with ASC-PVC: 10 in the ZF group (age 49 ± 16 years, 60% males) and 11 in the control group (age 47 ± 15 years, 27% males). Fluoroscopy was not required for any patient in the ZF group. Acute success was obtained in 80% of the ZF group vs 55% of the control group (P = .36). The recurrence rate was 30% in the ZF group vs 27% in the control group (P = 1). One nonsevere complication was observed in the ZF group (P = .48).

CONCLUSIONS

ZF catheter ablation of ASC-PVC guided by ICE 3D-EAM is feasible, effective, and safe.

Evaluation of five algorithms in predicting the sublocalisation of right ventricular outflow tract arrhythmia (RVOTA) when compared to 3D electroanatomical mapping origin

Purpose

To compare the predictive accuracy of five different algorithms as verified by successful ablation site using 3D electroanatomical non-contact mapping in patients with symptomatic and asymptomatic but high ventricular burden RVOT tachycardias.

Methods

28 Consecutive patients admitted for radiofrequency catheter ablation for symptomatic and asymptomatic, but high ventricular burden idiopathic VPC were recruited for this study. All patients had previous failed or intolerant to beta-blocker and/or at least one class IC anti-arrhythmic agents, and they had normal left ventricular ejection fraction. All patients had documented monomorphic VPC with left bundle branch block morphology and an inferior axis. Concordance of the arrhythmia origin based on ECG algorithm and 3D mapping system site were further evaluated. Of the five algorithms, two algorithms with easy‐applicability and having a memorable design (Dixit and Joshi) and three algorithms with more complex and detailed design (Ito, Zhang, Pytkowski) were selected for comparisons.

Results

Assessment of the diagnostic accuracy showed that each of the five algorithms had only moderate accuracy, and the greatest accuracy was observed in the algorithm proposed by Pytkowski algorithm when assessed by a general cardiologist and Dixit algorithm when evaluated by the electrophysiologist. However, when the algorithms were compared for their accuracy, specificity, sensitivity, no significant differences were found (p = 0.99).

Conclusions

The ECG based algorithms for precise localising RVOTA origin simplify the mapping process, reduce the procedural and fluoroscopic time, and improve clinical outcomes, resulting in greater clinical utility. All the five published 12-lead ECG algorithms for ROTVA differentiation were similar in terms of the diagnostic accuracy, specificity, sensitivity and LRs.

S-R index in V1/V3 serves as a novel criterion to discriminate idiopathic premature ventricular contractions originating from posteroseptal right ventricular outflow tract versus right coronary cusp

AIM

The current study aimed to establish a novel electrocardiographic (ECG) criterion for discrimination of idiopathic premature ventricular contractions (PVCs) originating from posteroseptal right ventricular outflow tract (sRVOT-p) versus right coronary cusp (RCC).

METHODS

A total of 76 patients with idiopathic PVCs who underwent mapping and successful ablation were retrospectively included. Among them, 37 patients had PVCs from sRVOT-p origin and 39 patients from RCC origin. The surface ECGs during PVCs were recorded. S-R different index in V1/V3 was calculated with the following formula of 0.134*V3R-0.133*V1S.

RESULTS

ECG characteristics showed wider total QRS duration, smaller R-wave amplitude on lead V2-V5, and larger S-wave amplitude on lead V1-V3 in sRVOT-p origin than RCC origin. Lead V3 was the most common transitional lead in two groups. Receiver operating characteristic (ROC) curve analysis showed that S-wave amplitude on lead V1 exhibited the largest AUC of 0.772, followed by the AUC of R-wave amplitude on lead V3 of 0.771. Subsequently, 0.134*V3R-0.133*V1S index was obtained by multiplication, subtraction, sum, and division of these ECG measurements, which exhibited the largest AUC of 0.808. The optimal cut-off value was -0.26 for differentiating RCC from sRVOT-p origin, with the sensitivity of 78.4% and specificity of 77.8%. Moreover, 0.134*V3R-0.133*V1S index was superior to previous criteria in analysis of PVCs originating from sRVOT-p and RCC.

CONCLUSIONS

0.134*V3R-0.133*V1S is a novel ECG criterion to discriminate sRVOT-p from RCC origin in patients with idiopathic PVCs, which may provide guidance for approach of radiofrequency catheter ablation.

Implementation of zero or near-zero fluoroscopy catheter ablation for idiopathic ventricular arrhythmia originating from the aortic sinus cusp

Complete elimination of fluoroscopy during radiofrequency ablation (RFA) of idiopathic ventricular arrhythmias (IVAs) originating from the aortic sinus cusp (ASC) is challenging. The aim was to assess the feasibility, safety and a learning curve for a zero-fluoroscopy (ZF) approach in centers using near-zero fluoroscopy (NOX) approach in IVA-ASC. Between 2012 and 2018, we retrospectively enrolled 104 IVA-ASC patients referred for ZF RFA or NOX using a 3-dimensional electroanatomic (3D-EAM) system (Ensite, Velocity, Abbott, USA). Acute, short and long-term outcomes and learning curve for the ZF were evaluated. ZF was completed in 62 of 75 cases (83%) and NOX in 32 of 32 cases (100%). In 13 cases ZF was changed to NOX. No significant differences were found in success rates between ZF and NOX, no major complications were noted. The median procedure and fluoroscopy times were 65.0 [45-81] and 0.0 [0-5] min respectively, being shorter for ZF than for NOX. With growing experience, the preference for ZF significantly increased-43% (23/54) in 2012-2016 vs 98% (52/53) in 2017-2018, with a simultaneous reduction in the procedure time. ZF ablation can be completed in almost all patients with IVA-ASC by operators with previous experience in the NOX approach, and after appropriate training, it was a preferred ablation technique. The ZF approach for IVA-ASC guided by 3D-EAM has a similar feasibility, safety, and effectiveness to the NOX approach.

Electrocardiographic and electrophysiological characteristics of idiopathic ventricular arrhythmias with acute successful ablation at the superior portion of the mitral annulus

BACKGROUND

We sought to identify the electrocardiographic and electrophysiological characteristics of ventricular arrhythmias (VAs), including idiopathic ventricular tachycardia (VT) and premature ventricular contractions (PVCs), with acute successful radiofrequency catheter ablation (RFCA) at the superior portion of the mitral annulus (SP-MA).

METHODS AND RESULTS

Among 437 consecutive patients who presented with VAs for RFCA, twenty-six patients with acute successful RFCA at the SP-MA were included in this study. The ratio of the amplitude of the first positive peak (if present) versus the nadir in the unipolar electrogram (EGM) was 0.00-0.03 (0.00) at the acute successful RFCA site. The time interval between the QRS onset and the maximum descending slope (D-Max) in the unipolar EGM (QRS-Uni) was 18.8 ± 13.6 ms. With bipolar mapping, the ventricular QRS (V-QRS) interval was 3.75-17.3 (11) ms, 6 (23.1%) patients showed the earliest V-QRS interval of 0 ms, and the other 20 patients (76.9%) showed a V-QRS interval of 10-54 ms. The RFCA start-to-effect time was 14.1 ± 7.2 s in 23 patients (88.5%). In the remaining 3 patients (11.5%), the mean duration of successful RFCA was not well defined due to the infrequent nature of clinical VAs during RFCA. Early (within 3 days) and late (1-year) recurrence rates were 23.1% (6 patients) and 26.9% (7 patients), respectively. VAs disappeared 3 days later due to delayed RFCA efficacy in 2 patients (7.7%). No complications occurred during the RFCA procedure or the one-year follow-up.

CONCLUSIONS

SP-MA VAs are a rare but distinct subgroup of VAs. Bipolar and unipolar EGM features can help to determine the optimal RFCA site, and the QRS-Uni interval may serve as a marker that could be used to guide RFCA.

Reappraisal of electrocardiographic criteria for localization of idiopathic outflow region ventricular arrhythmias

BACKGROUND

Electrocardiographic (ECG) criteria have been proposed to localize the site of origin of outflow region ventricular arrhythmias (VAs). Many factors influence the QRS morphology of VAs and may limit the accuracy of these criteria.

OBJECTIVE

The purpose of this study was to assess the accuracy of ECG criteria that differentiate right from left outflow region VAs and localize VAs within the aortic sinus of Valsalva (ASV).

METHODS

One hundred one patients (mean age 52 ± 16 years; 55 [54%] women) undergoing catheter ablation of right ventricular outflow tract (RVOT) or ASV VAs with a left bundle branch block, inferior axis morphology were studied. ECG measurements including V₂ transition ratio, transition zone index, R-wave duration index, R/S amplitude index, V₂S/V₃R index, V_1-3 QRS morphology, R-wave amplitude in the inferior leads were tabulated for all VAs. Comparisons were made between the predicted site of origin using these criteria and the successful ablation site.

RESULTS

Patients had successful ablation of 71 RVOT and 38 ASV VAs. For the differentiation of RVOT from ASV VAs, the positive predictive values and negative predictive values for all tested ECG criteria ranged from 42% to 75% and from 71% to 82%, respectively, with the V₂S/V₃R index having the largest area under the curve of 0.852. Morphological QRS criteria in leads V₁ through V₃ did not localize ASV VAs. The maximum R-wave amplitude in the inferior leads was the sole criterion demonstrating a significant difference between right ASV, right-left ASV commissure, and left ASV sites.

CONCLUSION

ECG criteria for differentiating right from left ventricular outflow region VAs and for localizing ASV VAs have a limited accuracy.

Left Ventricular Summit-Concept, Anatomical Structure and Clinical Significance

The left ventricular summit (LVS) is a triangular area located at the most superior portion of the left epicardial ventricular region, surrounded by the two branches of the left coronary artery: the left anterior interventricular artery and the left circumflex artery. The triangle is bounded by the apex, septal and mitral margins and base. This review aims to provide a systematic and comprehensive anatomical description and proper terminology in the LVS region that may facilitate exchanging information among anatomists and electrophysiologists, increasing knowledge of this cardiac region. We postulate that the most dominant septal perforator (not the first septal perforator) should characterize the LVS definition. Abundant epicardial adipose tissue overlying the LVS myocardium may affect arrhythmogenic processes and electrophysiological procedures within the LVS region. The LVS is divided into two clinically significant regions: accessible and inaccessible areas. Rich arterial and venous coronary vasculature and a relatively dense network of cardiac autonomic nerve fibers are present within the LVS boundaries. Although the approach to the LVS may be challenging, it can be executed indirectly using the surrounding structures. Delivery of the proper radiofrequency energy to the arrhythmia source, avoiding coronary artery damage at the same time, may be a challenge. Therefore, coronary angiography or cardiac computed tomography imaging is strongly recommended before any procedure within the LVS region. Further research on LVS morphology and physiology should increase the safety and effectiveness of invasive electrophysiological procedures performed within this region of the human heart.

Automated Localization of Focal Ventricular Tachycardia From Simulated Implanted Device Electrograms: A Combined Physics-AI Approach

Background: Focal ventricular tachycardia (VT) is a life-threating arrhythmia, responsible for high morbidity rates and sudden cardiac death (SCD). Radiofrequency ablation is the only curative therapy against incessant VT; however, its success is dependent on accurate localization of its source, which is highly invasive and time-consuming. Objective: The goal of our study is, as a proof of concept, to demonstrate the possibility of utilizing electrogram (EGM) recordings from cardiac implantable electronic devices (CIEDs). To achieve this, we utilize fast and accurate whole torso electrophysiological (EP) simulations in conjunction with convolutional neural networks (CNNs) to automate the localization of focal VTs using simulated EGMs. Materials and Methods: A highly detailed 3D torso model was used to simulate ∼4000 focal VTs, evenly distributed across the left ventricle (LV), utilizing a rapid reaction-eikonal environment. Solutions were subsequently combined with lead field computations on the torso to derive accurate electrocardiograms (ECGs) and EGM traces, which were used as inputs to CNNs to localize focal sources. We compared the localization performance of a previously developed CNN architecture (Cartesian probability-based) with our novel CNN algorithm utilizing universal ventricular coordinates (UVCs). Results: Implanted device EGMs successfully localized VT sources with localization error (8.74 mm) comparable to ECG-based localization (6.69 mm). Our novel UVC CNN architecture outperformed the existing Cartesian probability-based algorithm (errors = 4.06 mm and 8.07 mm for ECGs and EGMs, respectively). Overall, localization was relatively insensitive to noise and changes in body compositions; however, displacements in ECG electrodes and CIED leads caused performance to decrease (errors 16-25 mm). Conclusion: EGM recordings from implanted devices may be used to successfully, and robustly, localize focal VT sources, and aid ablation planning.

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias: executive summary

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.

Successful catheter ablation approach above the aortic sinus cusp eliminating a ventricular arrhythmia arising from the myocardial crescent beneath the interleaflet triangle: Late gadolinium enhancement magnetic resonance imaging assessment

A 61-year-old female with 50 000 ventricular premature contractions and a reduced left ventricular ejection fraction of 35% was referred to our center. Although the origin was considered to originate from the junction between the left and right coronary cusp, a single radiofrequency application above the aortic sinus cusp could eliminate it. LGE-MRI was able to reveal the exact location of the single RF lesion.

Ventricular ectopy from the non-coronary cusp: Pathophysiological and anatomical considerations

Non-coronary cusp (NCC) is a rare site for ventricular arrhythmias because it does not come into direct contact with the ventricular myocardium. Instead, the NCC comes in contact with the membranous septum near the His region. We describe a case of a young man with a ventricular ectopy who was successfully ablated in the NCC. In our case the much greater prematurity in the NCC than in the His region suggests that the arrhythmic site of origin is not in the peri-His area but most likely a myocardial extension adjoining the aortic root.

Catheter ablation of premature ventricular contractions originating from periprosthetic aortic valve regions

BACKGROUND

Little is known about the ablation outcomes of premature ventricular contractions (PVCs) that originate from the periprosthetic aortic valve (PPAV) regions of patients with aortic valve replacement (AVR).

METHODS AND RESULTS

Our study had 11 patients who underwent catheter ablation for PVCs arising from the PPAV regions (bioprosthetic aortic valve, n = 5; mechanical aortic valve, n = 6). The PVC characteristics, procedure characteristics, and efficacy of ablation were compared with the control group (n = 33). At baseline, the PPAV group had a lower left ventricular ejection fraction (mean [SD], 41% [12%] vs. 51% [8%]; p = .002). The rate of acute ablation success was 90.9% in the PPAV group. Ablation sites were identified above the left coronary cusp (LCC) and right coronary cusp commissure (LRCC) in one PVC, below the prosthetic valve in eight PVCs (four below LCC and four below LRCC), and within the distal coronary sinus in two PVCs. The mean procedure time, fluoroscopy time, and radiation in the PPAV group were all significantly greater than those in the control group (all p < .05). However, the number of radiofrequency ablation energy deliveries was not different. The PPAV group had a long-term success rate compared with the control group (72.7% vs. 87.9%, p = .48) and an increase of left ventricular ejection fraction from 43% to 49% after successful PVC ablation at follow-up (p < .001). Echocardiography showed no significant change in valve regurgitation after ablation. No new atrioventricular block occurred.

CONCLUSION

PVCs arising from PPAV regions can be successfully ablated in patients with prior AVR, without damaging the prosthetic aortic valve and atrioventricular conduction.

Management of tachyarrhythmias in pregnancy - A review

The most common arrhythmias detected during pregnancy include sinus tachycardia, sinus bradycardia, and sinus arrhythmia, identified in 0.1% of pregnancies. Isolated premature atrial or ventricular arrhythmias are observed in 0.03% of pregnancies. Arrhythmias may become more frequent during pregnancy or may manifest for the first time.

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.

Prognostic significance of accelerated ventricular response during radiofrequency ablation of premature ventricular complexes

Background

Accelerated ventricular response is frequently observed during radiofrequency ablation (RFA) of premature ventricular complexes (PVCs). We hypothesized that acceleration indicates an appropriate site and adequate injury to the arrhythmogenic tissue, and sought to investigate its value in predicting the outcome.

Methods

We retrospectively analyzed RFA procedures performed for PVCs in our institution from 2011 to 2019.

Results

Fifty-eight patients (29 male; age 42.7 ± 15.6 years) underwent 62 RFA procedures. The most common site was the right ventricular outflow tract (67.7%). Acute success was seen in 88.7%. Accelerated ventricular response was observed in 60.0% of the successful procedures. After a median follow-up of 14.0 months (IQR: 6.0–26.6 months), 16 patients had a recurrence. Recurrence was significantly lower in the group with acceleration than in the group without acceleration (12.5% vs. 57.1%; log-rank P < 0.001). The 1-year recurrence rate was 6.5% in the acceleration group and 41.6% in the group without acceleration. On multivariable analysis the adjusted hazard ratio was 0.17 (95% CI, 0.04–0.64; Cox regression P = 0.009). The sensitivity, specificity, positive predictive, and negative predictive values of accelerated response to predict long-term success were 75.7%, 75.0%, 87.5%, and 57.2%, respectively.

Conclusions

The recurrence after PVC ablation is significantly lower when an accelerated response was observed at the successful location during RFA. This can be an additional useful marker of long-term success.

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias: Executive summary

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.

Applicability of computed tomography preoperative assessment of the LAA in LV summit ablations

Purpose

Ventricular arrhythmias originating from the left ventricular summit (LVS) may present with challenges for catheter ablation. Recently, the left atrial appendage (LAA) became a new vantage point for mapping and ablating arrhythmias from that region, but data of possible usefulness is limited.

Methods

From September to December 2019, we retrospectively analyzed 48 consecutive patient hearts (20 male; mean age 57.9y ± 11.56) undergoing diagnostic coronary vessel imaging in 64 dual-source computer tomography angiography (CTA). Distances from the LAA to the LVS, LAA shape type, and coronary arteries in the LVS region were measured. Also, we compared the true LVS area from CTA with a calculated formula derived from LVS definition.

Results

The mean LVS area calculated from the formula was 291.58 mm² (± 115.5) while the true area calculated from CT was 263.33 mm² (± 99.49) (p = 0.44). The mean inaccessible area was 133.42 mm² (± 72.89), accessible 95.67 mm² (± 72.77). The mean LAA coverage over LVS was 196.08 mm²—which is approximately 75% of LVS size in general. The most common LAA shape was chicken wing (50%); windsock has the highest accessible area coverage on average (80.23%), followed by chicken wing (59.88%), broccoli (47.72%), and cactus (46.98%). The mean distance from LAA to the surface was 5.14 mm (1.5 to 10 mm) and was not correlated with BMI. LAA has a 98% coverage over the point of transition between the great cardiac vein and anterior interventricular vein.

Conclusion

Angio-CT assessment of the LAA over the LVS structures may be helpful in decision making before an ablation procedure. LAA appears to be a promising mapping approach in LVS arrhythmias.

Electrocardiographic characteristics of idiopathic ventricular arrhythmias based on anatomy

Idiopathic ventricular arrhythmia (IVA) is a term used to describe a spectrum of ventricular arrhythmia without structural heart disease (SHD). IVAs contain premature ventricular contractions (PVCs), nonsustained monomorphic ventricular tachycardia (VT), and sustained VT. Electrocardiography is a fundamental and important tool to diagnose and localize IVAs. More detailed, IVAs originating from different origins exhibit characterized ECGs due to their specific anatomic backgrounds. As catheter ablation becomes widely used to eliminate these arrhythmias, its high success rate is based on accurate localization of their origins. Therefore, these ECG characteristics show great importance for precise localization of their origins and subsequently successful ablation. This review aims to sum up ECG characteristics of IVAs based on anatomy and give brief introduction of mechanisms and treatment of IVAs.

The aortic cusps are the predominant successful ablation site of idiopathic outflow-tract ventricular arrhythmias

BACKGROUND

Data regarding the successful ablation site of idiopathic outflow tract (OT) ventricular arrhythmias (VAs) in the modern era of mapping and ablation are limited.

METHODS AND RESULTS

Over a 4-year period, a total of 309 patients underwent detailed activation mapping of OT VAs including the right ventricular outflow tract (RVOT), the left ventricular outflow tract (LVOT) and the aortic cusps (AC), and the coronary venous system. 244 cases were successfully ablated at the index procedure (78.9%). The successful ablation site was more frequently located at the LVOT/ACs (51.6%) followed by RVOT (36.2%). In particular, the ACs was the predominant successful ablation site of idiopathic OT VAs (46.7%). An epicardial site of origin was predictor of ablation failure (p < 0.05).

CONCLUSIONS

The ACs is the predominant successful ablation site of idiopathic OT VAs.

TAKE-HOME MESSAGE

The aortic cusps are the predominant successful ablation site of idiopathic idiopathic outflow tract ventricular arrhythmias.

Concealed structural heart disease discovered at cardiac magnetic resonance in patients with ventricular extrasystoles from ventricular outflow tract and apparently normal hearts

BACKGROUND

Outflow tract (OT) premature ventricular contractions (PVCs) are commonly found in clinical practice; in most cases, PVCs are benign and observed in structurally normal hearts, not requiring any therapeutic intervention. In this study, we therefore sought to evaluate with cardiac magnetic resonance (CMR) patients with PVC and apparently normal heart at echocardiographic examination, in order to identify possible substrates linked with higher prevalence of arrhythmias or structural heart disease.

METHODS

Thirty-three consecutive patients with frequent PVCs originating from the ventricular OT (right and left) were enrolled in the study and assessed by echocardiography and CMR. All patients had normal baseline electrocardiogram.

RESULTS

CMR showed structural changes in 5 patients out of 33; in 3 cases, areas of fibrosis limited in one case to the middle basal segments of the interventricular septum and in two patients to the middle basal segments of the inferior-lateral wall were found. In 2 other cases, however, late gadolinium enhancement showed significant anomalies characterized in one patient by extensive areas of subepicardial fibrosis of the left ventricle, suitable with arrhythmogenic left dominant dysplasia; in another patient, a marked trabeculation of left ventricular medium apical segments suitable with non-compaction myocardium was present.

CONCLUSIONS

CMR may identify cases of structural heart disease in subjects with OT PVCs and apparently normal electrocardiogram and echocardiogram examinations. A preliminary screening with CMR may be considered before any further invasive electrophysiology assessment and therapeutic planning.

Recent advances in three-dimensional electroanatomical mapping guidance for the ablation of complex atrial and ventricular arrhythmias

PURPOSE

To provide a brief overview of some relevant technological advances in the field of three-dimensional electroanatomical mapping (3D-EAM) that have recently entered the clinical arena and their role in guiding catheter ablation (CA) of complex atrial and ventricular arrhythmias.

METHODS

In this technical report, we describe the general features of three novel algorithms featured in the updated CARTO PRIME™ mapping module for CARTO®3 version 7 3D-EAM system (Biosense Webster Inc., Diamond Bar, CA, USA): local activation time (LAT) hybrid, coherent mapping and map replay modules. We also report three challenging arrhythmia cases in which CA was successfully guided by these softwares.

RESULTS

The LAT hybrid module was used in a case of premature ventricular complex originating from the right coronary cusp. This algorithm facilitated safe positioning of the ablation catheter away from the right coronary ostium, avoiding potential harm to this vital structure. The coherent mapping module helped to identify the critical as well as a bystander isthmus of an atrial macro-re-entrant tachycardia in a grown-up patient with congenital heart disease. The map replay module allowed rapid retrospective activation mapping of two unstable ventricular tachycardias in a case of nonischemic cocaine-associated cardiomyopathy.

CONCLUSION

3D-EAM systems offer significant advantages in the management of challenging arrhythmias, and the introduction of novel algorithms underpins improvements in patients' outcomes. Given the increasing sophistication of these systems, however, a close collaboration among cardiac electrophysiologists, engineers and technicians is highly needed in order to get the best from the available technology.

Periaortic ventricular tachycardia in structural heart disease: Evidence of localized reentrant mechanisms

BACKGROUND

The mechanisms for scar-related ventricular tachycardia (VT) originating from the periaortic region remain incompletely characterized.

OBJECTIVE

The purpose of this study was to map the circuits responsible for periaortic VT in high resolution.

METHODS

Cases with periaortic VT (2016-2020) were analyzed to characterize the substrate and mechanisms with multielectrode mapping. Periaortic VT was defined as low-voltage and/or deceleration zones within 2 cm of the left ventriculoaortic junction with a corresponding critical site during VT.

RESULTS

Forty-nine periaortic monomorphic VTs were analyzed in 30 patients (25% of all patients with nonischemic cardiomyopathy). Isolated periaortic substrate was observed in 27% of patients, with 73% having concomitant scar, most commonly in the mid-septum (47%). Deceleration zones were equally prevalent on the septal and lateral portions of the periaortic region (87% vs 73%; P = .19). During activation mapping of VT (tachycardia cycle length 392 ± 105 ms), localized reentrant patterns of activation (14 mm [10-17 mm] × 10 mm [7-14 mm]) were demonstrated in 63% and 37% of VTs showed centrifugal activation, consistent with a focal breakout pattern. Ninety-three percent of VTs fulfilled criteria for a reentrant mechanism. Sixty-five percent of reentrant circuits had endocardial activation gaps within the tachycardia cycle length (3-dimensional circuitry), which were associated with higher rates of recurrence as compared with 2-dimensional complete circuits at 1 year (73% vs 37%; P = .028).

CONCLUSION

Periaortic VTs were observed in 25% of patients with nonischemic cardiomyopathy and scar-related VT. For the first time, localized reentry confined to this anatomically challenging region was demonstrated as the predominant mechanism by high-resolution circuit activation mapping.